On the Search and Localization of Platinum-Group Microelements in Samples of the Chromite Horizon in the Bushveld Complex

The search for microinclusions of light platinoids (Ru and Pd) in samples of the Bushveld intrusion complex (South Africa) and corresponding examination are performed by scanning X-ray fluorescence analysis at the SR XRF experimental station with the help of the VEPP-3 storage ring at the Collective-Use Center Siberian Synchrotron and Terahertz Radiation Center based at the Budker Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences. The samples are prepared as plane parallel ground plates 2 mm in thickness. First, one-dimensional scanning with a wide beam (1 x 20 mm) of monochromatic radiation with an excitation energy of 20 and 30 keV is performed. Then, the region with higher contents of light platinoids is two-dimensionally scanned with a beam (30 x 45 mu m) which is focused with a polycapillary lens. Sample surface mapping enables identification of a few individual particles 50-100 mu m in size with a high Pd content. The potential for micro-XAFS investigation of an individual particle is demonstrated.